Currently, organic electroluminescent display (OLED) panels are becoming dominant in the display field due to characteristics such as low power consumption, high color saturation, wide angle of view, slim thickness, no requirement for light source, flexible, and so on.
The basic structure of an OLED includes a base substrate, and an anode, a light emitting layer and a cathode subsequently provided on the base substrate. Its principle for emitting light is that, when a voltage is applied across the anode and the cathode to provide a current, electrons from the cathode are recombined with holes from the anode at the light emitting layer to form excitons, so that the organic material in the light emitting layer is excited to emit light. The light emitting layer can be made by an inkjet printing technology, and generally, before preparing the light emitting layer, a pixel definition layer can be made on the base substrate on which the anode has been formed, to define the position for the pixel area, after that, the light emitting layer is formed in an opening region corresponding to the pixel area in the pixel definition layer, and finally, a film layer for the cathode is made on the light emitting layer